The present application claims priority under 35 U.S.C. xc2xa7119 to Japanese Patent Application No. 2001-023454, filed Jan. 31, 2001, entitled xe2x80x9cFUEL SYSTEM PARTxe2x80x9d. The contents of this application are incorporated herein by reference in their entirety.
1. Field of the Invention
The present invention relates to a fuel system part consisting of a resin material. More particular, the present invention relates to a fuel system part having excellent fuel permeation resistance and having excellent shock impact resistance and heat resistance.
2. Discussion of the Background
Conventionally, as automobile fuel system parts such as fuel tanks and valves, there has been applied an HDPE (high density polyethylene) which is excellent in shock impact resistance and chemical resistance and can reduce cost. However, the HDPE has large intermolecular spaces and low cohesive power. Thus, there is a problem that fuel permeation properties are great. Recently, as an environmental restriction, evaporation restriction is provided, and it is required to suppress evaporation of hydrocarbon. Thus, there is a growing need for a material for fuel system parts with excellent fuel permeation resistance. However, in the conventional HDPS, it is difficult to cope with the foregoing problem for the above reasons.
Recently, although a material such as polyamide 12 or polyamide 6 is considered as a material having excellent fuel permeation resistance, such material is inferior to the HDPE in shock impact resistance, and is inferior to an alcohol-containing fuel in fuel permeation resistance.
As materials with permeation resistance to the alcohol-containing fuels, there are employed a liquid crystal polymer, polyketone, PBT, PPS and the like. However, there is a disadvantage that these materials are inferior in toughness or shock impact resistance.
The inventor found out an alloy material of a polyphenylene sulfide resin (hereinafter, referred to as a PPS resin) and an olefin-based resin as a material with very excellent fuel permeation resistance and excellent shock impact resistance and heat resistance that are reverse characteristics.
An object of the present invention is to provide fuel system part with excellent fuel permeation resistance and excellent shock impact resistance and heat resistance.
According to one aspect of the present invention, there is provided a fuel system part consisting of a resin composition, wherein the resin composition comprises (a) a polyphenylene sulfide resin and (b) an olefin based resin, wherein an amount of the (a) polyphenylene sulfide resin and the (b) olefin based resin is 80 weight % or more of the entire resin composition and the content of the (b) olefin based resin is 10 to 100 parts by weight relevant to 100 parts by weight of the (a) polyphenylene sulfide resin, and wherein the resin composition has a fuel permeability coefficient (Fuel C/ethanol=90/10) of 3.3xc3x9710xe2x88x9216 molxc2x7m/m2xc2x7sxc2x7Pa or less at 40xc2x0 C.